Process for converting petroleum coke to a nitrogen containing fertilizermulch

ABSTRACT

PETROLEUM COKE IS CONVERTED TO A PRODUCT CONTAINING UP TO 12.3% NITROGEN BY AMMOXIDATION OF THE COKE FOLLOWED BY TREATING THE AMMOXIDIZED PRODUCT WITH CONCENTRATED NITRIC ACID AND NEUTRALIZING THE RESULTING PRODUCT WITH CONCENTRATED AMMONIUM HYDROXIDE. IF THE INITIAL AMMOXIDATION STEP IS OMITTED A PRODUCT CONTAINING AROUND 7% NITROGEN IS OBTAINED. THE PRODUCT WILL NOT HARM PLANTS AND ACTS AS A MULCH AFTER ITS NITROGEN HAS BEEN DEPLETED. A MICRONUTRIENT SUCH AS BORAX OR A SIMILAR WATER-SOLUBLE SALT CAN BE ADDER EITHER DURING THE AMMOXIDATION OR THE NEUTRALIZATION STEPS TO FORM A PRODUCT WHICH IS BOTH A MICRONUTRIENT AND A SOURCE NITROGEN.

United States Patent O PROCESS FOR CONVERTING PETROLEUM COKE TO A NITROGEN CONTAINING FERTILIZER- MULCH William P. Doyle, Lagrangeville, Robert Y. Heisler, Wappingers Falls, and John A. Patterson, Fishkill, N.Y., assignors to Texaco Inc., New York, N.Y. No Drawing. Filed Nov. 24, 1969, Ser. No. 879,521

Int. Cl. COSf 11/02 US. Cl. 711 9 Claims ABSTRACT OF THE DISCLOSURE Petroleum coke is converted to a product containing up to 12.3% nitrogen by ammoxidation of the coke folowed by treating the ammoxidized product with concentrated nitric acid and neutralizing the resulting product with concentrated ammonium hydroxide. If the initial ammoxidation step is omitted a product containing around 7% nitrogen is obtained. The product will not harm plants and acts as a mulch after its nitrogen has been depleted. A micronutrient such as borax or a similar water-soluble salt can be adder either during the ammoxidation or the neutralization steps to form a product which is both a micronutrient and a source of nitrogen.

BACKGROUND OF THE INVENTION This invention is concerned with a process for converting petroleum coke to a nitrogen containing fertilizer mulch.

Conversion of coal or of its derivatives into useful plant nutrients has been sought for many years. Among the attempts made to arrive at such nutrients has been the treatment of humic acids by ammonium hydroxide or nitric acid. The resulting products, however, were very water soluble and lost a substantial amount of their nitrogen before reaching the plants.

In a newer process, pulverized low-grade coal has been reacted with amonia and the ammoniated coal has been treated with nitric acid and ammonium hydroxide to give an end product containing 20-22% nitrogen about one third of which exists in an ammonium salt form quickly available to plants while the remainder of its nitrogen is heterocyclically bound and more slowly released.

Heretofore to our knowledge petroleum coke has not successfully been converted into fertilizer mulch probably because it is more refractory and harder to chemically modify than coal.

The main object of our invention is to provide a process for economically converting petroleum coke into a dual purpose product serving as both fertilizer and mulch.

Another object of the invention is to prepare a fertilizermulch from petroleum coke which is a micronutrient source as well as a nitrogen source. This object is attained by including 0.05 to 0.5 part per part of coke of a water soluble salt of the micronutrient in the ammoxidation or subsequent step in the preparation of the fertilizer-mulch. Micronutrients useful in the practice of the invention are copper, zinc, iron, manganese, sulfur and boron. Suitable salts for the process are copper sulfate, zinc sulfate, iron sulfate, manganese sulfate, borax or other water soluble salts of copper, zinc, manganese and iron.

SUMMARY OF THE INVENTION In the practice of the claimed invention, whereby the foregoing objects are attained, 1 part of finely divided coke is heated with 0.4-0.7 part of NH and 3.6-3.3 parts of water to around 250-600 F. under 450-1800 p.s.i.g. oxygen pressure until ammoxidation thereof is substantially complete. The ammoxidized coke then is nitrated by slowly 3,595,638 Patented July 27, 1971 contacting it with about 2.5 parts of 70% HNO at around 115 F. and after the addition of HNO is complete the resulting mixture is heated to above 200 F. The reaction mixture is cooled, the product filtered off and dried. From 100 to 200% by volume of ammonium hydroxide is slowly added to the product with agitation and the product is filtered and dried. Products containing up to 12.3% nitrogen are obtained. The process of the invention can also be carried out with the omission of the ammoxidation step. The resulting product then has a lower nitrogen content of the order of around 7% nitrogen.

The following examples illustrate but do not limit the invention:

Example 1 A mixture of 40 parts 12-15 mesh petroleum coke, 100 parts conc. ammonium hydroxide and 60 parts water was heated at 440-486 F. under 650-850 p.s.i.g. oxygen pressure in a stainless steel autoclave for 11% hours. After cooling and releasing the pressure, 40 parts ammoxidized coke containing 4.7% nitrogen was obtained. (The coke charge contained 2.7% nitrogen).

To 37.5 parts of the above ammoxidized coke was added dropwise 100 parts of cone. nitric acid during a period of 1% hours keeping the temperature below 115 F. After addition was complete the mixture was heated to a temperature of 220 F. during a period of about 5 hours. The reaction mixture was cooled and the product was filtered off and air dried.

To this dried material parts conc. ammonium hydrodide was added dropwise with stirring during 1% hours. The product was filtered and air dried overnight. Sixty parts of a product, useful as a fertilizer mulch, and containing 12.3% nitrogen, was obtained.

Example 2 A similar run made in the same way except that the ammoxidation step was omitted. The final product contained 7.8% nitrogen.

Example 3 A mixture of 40 parts 12-25 mesh petroleum coke, parts conc. ammonium hydroxide, 5 grams copper sulfate and 60 parts water was heated at 550-5 54 F. under 1100- 1175 p.s.i.g. oxygen pressure in a stainless steel autoclave for 9 hours. After cooling and releasing the pressure 39.5 parts ammoxidized coke was obtained. The charge coke contained 1.4% nitrogen, 1.38% sulfur and 0% copper while the ammoxidized coke contained 3.0% nitrogen, 1.2% sulfur and 1.7% copper.

To 39 parts of the above ammoxidized coke was added dropwise 100 parts of concentrated nitric acid during a period of 40 minutes keeping the temperature below 73 F. After addition was complete the mixture was heated to a temperature of up to 206 F. during a period of about 5% hours. The reaction mixture was cooled and the product was filtered off and dried. The product amounted to 51.5 parts.

To 25 parts of the above material, 45 parts concentrated ammonium hydroxide were added dropwise with stirring during /2 hour. The product was filtered and air dried on a steam plate. 26 parts of a product containing 9.5% nitrogen, 0.63% sulfur and 0.41% copper, useful as a fertilizer-mulch and micronutrient source, was obtained.

Example 4 25 parts of the product from the above nitric acid reaction were treated with 45 parts ammonium hydroxide and 5 parts copper sulfate. The fertilizer mulch obtained (26.3 parts) contained 9.2% nitrogen, 1.1% sulfur and 3.94% copper.

By following essentially the procedure of Examples 3 and 4 but using instead of copper, zinc sulfate, iron sulfate, manganese sulfate and borax and mixtures thereof, there are obtained fertilizer mulches containing those elements as micronutrient sources.

It will be appreciated that the ammoxidation step can be carried out with pressurized air instead of oxygen. Similarly, apparatus other than an autoclave can be used for scaled up operation.

As regards the reactants, petroleum coke of any source is suitable although for the economics of the process it will be preferred to use coke obtained by the coking of industrial organic wastes. Optimum results will be obtained if the coke has a mesh size of between 15-25 and --100.

The nitric acid and the ammonium hydroxide which are used in the claimed process preferably are concentrated but concentrations thereof as low as 50% for the nitric acid and 50% for the ammonium hydroxide also are operative.

What is claimed is:

1. A process for converting petroleum coke to a nitrogen-containing fertilizer-mulch comprising the steps of reacting the coke with nitric acid and neutralizing the resulting product with ammonium hydroxide to form a product.

2. The process according to claim 1 wherein the coke is ammoxidized preceding the reaction with nitric acid to obtain a product containing about 12% of nitrogen.

3. The process according to claim 2 wherein said ammoxidation is carried out at about 250-600 F. under around 450-1800 p.s.i.g. oxygen pressure.

4. The process according to claim 2 wherein said reaction with nitric acid is carried out at a temperature not in excess of 115 F. and then heating the resulting product to a temperature of 200 F.

5. The process according to claim 2 wherein a micronutrient is included in said ammoxidation step to form a product useful also as a micronutrient source.

6. The process according to claim 2 wherein a micronutrient is added during said neutralizing to form a product useful also as a micronutrient source.

7. The process according to claim 5 wherein said micronutrient is selected from the group consisting of the water soluble salts of copper, zinc, iron, manganese, sulfur, boron and mixtures thereof, said micronutrient being present in an amount ranging from 0.05 to 0.5 part per part of coke.

8. The process according to claim 6 wherein said micronutrient is selected from the group consisting of the water soluble salts of coper, zinc, iron, manganese, sulfur, boron and mixtures thereof, said micronutrient being present in an amount ranging from 0.05 to 0.5 part per part of coke.

9. A fertilizer-mulch product useful also as a micronutrient source and produced by ammoxidizing coke: reacting the ammoxidized coke with nitric acid and neutralizing with ammonium hydroxide with the addition of a micronutrient either during the ammoxidizing or the neutralizing step.

References Cited UNITED STATES PATENTS 8/1939 Smit 71-29X 5/1949 Higgins 71-1X U. S. Cl. X.R. 71-24, 25, 43 

